Open the emoji autocomplete by typing : followed by two characters of the word describing the emoji. A full list of emojis can be found here. It is also possible to create your own Custom Emoji if the emoji you want to use doesn’t exist.

To add syntax highlighting, type the language to be highlighted after the ``` at the beginning of the code block. Mattermost also offers four different code themes (GitHub, Solarized Dark, Solarized Light, Monokai) that can be changed in Account Settings > Display > Theme > Custom Theme > Center Channel Styles

Add in-line images by using an exclamation mark followed by the alt text in square brackets then the URL of the image in round brackets. You can add hover text by placing the text in quotes after the link.

![{alt text}]({URL of image} “{Hover text} ” )

If the height of the original image is more than 500 pixels, the system sets the height at 500 pixels and adjusts the width to maintain the original aspect ratio.

You can set the width and height of the displayed image by using an equals sign and the width x height after the URL of the image. If you set only the width, the system adjusts the height to maintain the original aspect ratio.

Create a table by placing a dashed line under the header row and separating the columns with a pipe |. (The columns don’t need to line up exactly for it to work). Choose how to align table columns by including colons : within the header row.